An RV played a warning message before it exploded in downtown Nashville, police say. Authorities have found what they believe to be human remains near the site.

Three civilians who were injured are in stable condition. At least 41 businesses were damaged, the mayor said.

Latest developments

• Police tweeted a photo of the RV and said it arrived on 2nd Avenue at 1:22 a.m.

• One witness said three vehicles were among the many objects on fire after the blast.

• Mayor Cooper issued a curfew for the area surrounding the explosion site. The curfew lasts until 4:30 p.m. Sunday.

Recorded voice counted down

Metro Nashville Police Department officers were responding to a call of shots fired around 5:30 a.m. CT Friday when they found a motor home parked in front of an AT&T transmission building at 166 2nd Avenue North.

Nashville Vice Mayor Jim Shulman told CNN’s Anderson Cooper that a female voice was speaking in the warning message played from the RV before the explosion.

“There were a number of people who did evacuate and then we know of some people, it didn’t go off when the message said it would and so people started coming back in, and then it went off,” he explained.

Officers saw no immediate evidence of shots fired but they requested the department’s hazardous devices unit and started to evacuate neighborhood residents, police said.

The RV exploded at 6:30 a.m. CT as the bomb squad was responding, police spokesman Don Aaron said.

“We do believe this to have been an intentional act,” he said.

Authorities: No credible threats signaling impending attack before Christmas

The force of the explosion knocked down one officer, Aaron said, and caused hearing loss in another — hopefully temporarily, he said. But no officers were significantly injured.

A vehicle is on fire after an explosion in Nasvhille on Friday, December 25, 2020.

Officials have no information about whether anyone was inside the RV when it exploded.

There were no known credible threats in the Nashville area that would have signaled an impending attack on or before Christmas, a federal law enforcement source told CNN.

A second law enforcement source said federal authorities are not aware of any increased chatter nationally by known extremist groups that would indicate any credible plans for conducting attacks around the holidays.

Acting US Attorney General Jeff Rosen was briefed on the incident, according to his spokesman, “and directed that all DOJ resources be made available to assist in the investigation.”

The White House said that President Donald Trump has been briefed and would receive “regular updates.” President-elect Joe Biden has also been briefed.

Tennessee Gov. Bill Lee said in a statement on Twitter that the state would “supply all the resources needed” to determine the cause of the explosion.

‘Everything on the street was on fire’

Buck McCoy told CNN the explosion took place right in front of his home, causing his windows to be blown in.

“Everything on the street was on fire,” he said. “There were three cars that were fully engulfed.”

McCoy said he was originally woken up by what he believed were gunshots prior to the explosion. He got up and looked out the window, he said, but went back to bed when he didn’t see anything.

Asked if the noise he heard could have been something other than gunfire, McCoy emphasized that he believed it was, saying he owns a gun and goes shooting, so he’s familiar with the sound of gunshots.

McCoy told CNN that when he looked outside after the explosion, trees had fallen and broken glass was everywhere. He saw people filing out of their apartments with their animals. Firefighters told him to get as far away from the area as possible, he said.

“There’s just nothing left on 2nd Avenue,” he said.

Emergency personnel work at the scene of the explosion.

‘Lives were saved’ by evacuations

Prior to the explosion, officers had gone door-to-door or apartment-to-apartment to inform residents of the situation, Aaron said. One man walking a dog on 2nd Avenue was redirected by an officer just before the RV exploded.

“We think lives were saved by those officers doing just that,” Aaron said Friday afternoon.

Technical experts from the FBI lab and evidence response teams have been brought in from around the country to “help process this massive crime scene,” Foster said.

ATF Special Agent in Charge Mickey French said his agency had activated its national response teams and was working alongside the FBI and MNPD. The agency has explosive specialists, chemists and engineers involved in the evidence recovery process.

Smoke rises from downtown Nashville after an explosion.

The street is on the edge of the Tennessee city’s hospitality and tourist district in a historic part of town.